233 lines
8.9 KiB
C++
233 lines
8.9 KiB
C++
// Copyright Kevlin Henney, 2000-2005.
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// Copyright Alexander Nasonov, 2006-2010.
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// Copyright Antony Polukhin, 2011-2020.
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// what: lexical_cast custom keyword cast
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// who: contributed by Kevlin Henney,
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// enhanced with contributions from Terje Slettebo,
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// with additional fixes and suggestions from Gennaro Prota,
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// Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov,
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// Alexander Nasonov, Antony Polukhin, Justin Viiret, Michael Hofmann,
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// Cheng Yang, Matthew Bradbury, David W. Birdsall, Pavel Korzh and other Boosters
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// when: November 2000, March 2003, June 2005, June 2006, March 2011 - 2014
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#ifndef BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
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#define BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
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#include <boost/config.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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# pragma once
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#endif
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#if defined(__clang__) || (defined(__GNUC__) && \
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!(defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || defined(__ECC)) && \
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(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wuninitialized"
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#pragma GCC diagnostic ignored "-Wsign-conversion"
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#endif
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#include <string>
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#include <boost/type_traits/is_integral.hpp>
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#include <boost/type_traits/type_identity.hpp>
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#include <boost/type_traits/conditional.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/type_traits/is_arithmetic.hpp>
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#include <boost/lexical_cast/detail/is_character.hpp>
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#include <boost/lexical_cast/detail/converter_numeric.hpp>
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#include <boost/lexical_cast/detail/converter_lexical.hpp>
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#include <boost/range/iterator_range_core.hpp>
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#include <boost/container/container_fwd.hpp>
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namespace boost {
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namespace detail
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{
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template<typename T>
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struct is_stdstring
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: boost::false_type
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{};
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template<typename CharT, typename Traits, typename Alloc>
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struct is_stdstring< std::basic_string<CharT, Traits, Alloc> >
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: boost::true_type
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{};
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// Sun Studio has problem with partial specialization of templates differing only in namespace.
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// We workaround that by making `is_booststring` trait, instead of specializing `is_stdstring` for `boost::container::basic_string`.
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template<typename T>
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struct is_booststring
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: boost::false_type
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{};
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template<typename CharT, typename Traits, typename Alloc>
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struct is_booststring< boost::container::basic_string<CharT, Traits, Alloc> >
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: boost::true_type
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{};
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template<typename Target, typename Source>
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struct is_arithmetic_and_not_xchars
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{
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typedef boost::integral_constant<
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bool,
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!(boost::detail::is_character<Target>::value) &&
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!(boost::detail::is_character<Source>::value) &&
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boost::is_arithmetic<Source>::value &&
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boost::is_arithmetic<Target>::value
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> type;
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BOOST_STATIC_CONSTANT(bool, value = (
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type::value
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));
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};
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/*
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* is_xchar_to_xchar<Target, Source>::value is true,
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* Target and Souce are char types of the same size 1 (char, signed char, unsigned char).
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*/
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template<typename Target, typename Source>
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struct is_xchar_to_xchar
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{
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typedef boost::integral_constant<
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bool,
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sizeof(Source) == sizeof(Target) &&
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sizeof(Source) == sizeof(char) &&
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boost::detail::is_character<Target>::value &&
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boost::detail::is_character<Source>::value
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> type;
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BOOST_STATIC_CONSTANT(bool, value = (
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type::value
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));
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};
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template<typename Target, typename Source>
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struct is_char_array_to_stdstring
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: boost::false_type
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{};
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template<typename CharT, typename Traits, typename Alloc>
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struct is_char_array_to_stdstring< std::basic_string<CharT, Traits, Alloc>, CharT* >
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: boost::true_type
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{};
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template<typename CharT, typename Traits, typename Alloc>
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struct is_char_array_to_stdstring< std::basic_string<CharT, Traits, Alloc>, const CharT* >
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: boost::true_type
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{};
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// Sun Studio has problem with partial specialization of templates differing only in namespace.
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// We workaround that by making `is_char_array_to_booststring` trait, instead of specializing `is_char_array_to_stdstring` for `boost::container::basic_string`.
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template<typename Target, typename Source>
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struct is_char_array_to_booststring
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: boost::false_type
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{};
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template<typename CharT, typename Traits, typename Alloc>
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struct is_char_array_to_booststring< boost::container::basic_string<CharT, Traits, Alloc>, CharT* >
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: boost::true_type
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{};
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template<typename CharT, typename Traits, typename Alloc>
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struct is_char_array_to_booststring< boost::container::basic_string<CharT, Traits, Alloc>, const CharT* >
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: boost::true_type
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{};
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template <typename Target, typename Source>
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struct copy_converter_impl
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{
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// MSVC fail to forward an array (DevDiv#555157 "SILENT BAD CODEGEN triggered by perfect forwarding",
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// fixed in 2013 RTM).
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#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && (!defined(BOOST_MSVC) || BOOST_MSVC >= 1800)
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template <class T>
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static inline bool try_convert(T&& arg, Target& result) {
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result = static_cast<T&&>(arg); // eqaul to `result = std::forward<T>(arg);`
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return true;
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}
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#else
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static inline bool try_convert(const Source& arg, Target& result) {
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result = arg;
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return true;
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}
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#endif
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};
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}
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namespace conversion { namespace detail {
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template <typename Target, typename Source>
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inline bool try_lexical_convert(const Source& arg, Target& result)
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{
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typedef BOOST_DEDUCED_TYPENAME boost::detail::array_to_pointer_decay<Source>::type src;
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typedef boost::integral_constant<
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bool,
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boost::detail::is_xchar_to_xchar<Target, src >::value ||
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boost::detail::is_char_array_to_stdstring<Target, src >::value ||
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boost::detail::is_char_array_to_booststring<Target, src >::value ||
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(
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boost::is_same<Target, src >::value &&
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(boost::detail::is_stdstring<Target >::value || boost::detail::is_booststring<Target >::value)
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) ||
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(
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boost::is_same<Target, src >::value &&
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boost::detail::is_character<Target >::value
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)
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> shall_we_copy_t;
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typedef boost::detail::is_arithmetic_and_not_xchars<Target, src >
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shall_we_copy_with_dynamic_check_t;
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// We do evaluate second `if_` lazily to avoid unnecessary instantiations
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// of `shall_we_copy_with_dynamic_check_t` and improve compilation times.
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typedef BOOST_DEDUCED_TYPENAME boost::conditional<
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shall_we_copy_t::value,
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boost::type_identity<boost::detail::copy_converter_impl<Target, src > >,
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boost::conditional<
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shall_we_copy_with_dynamic_check_t::value,
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boost::detail::dynamic_num_converter_impl<Target, src >,
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boost::detail::lexical_converter_impl<Target, src >
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>
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>::type caster_type_lazy;
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typedef BOOST_DEDUCED_TYPENAME caster_type_lazy::type caster_type;
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return caster_type::try_convert(arg, result);
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}
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template <typename Target, typename CharacterT>
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inline bool try_lexical_convert(const CharacterT* chars, std::size_t count, Target& result)
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{
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BOOST_STATIC_ASSERT_MSG(
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boost::detail::is_character<CharacterT>::value,
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"This overload of try_lexical_convert is meant to be used only with arrays of characters."
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);
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return ::boost::conversion::detail::try_lexical_convert(
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::boost::iterator_range<const CharacterT*>(chars, chars + count), result
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);
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}
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}} // namespace conversion::detail
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namespace conversion {
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// ADL barrier
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using ::boost::conversion::detail::try_lexical_convert;
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}
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} // namespace boost
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#if defined(__clang__) || (defined(__GNUC__) && \
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!(defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || defined(__ECC)) && \
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(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))
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#pragma GCC diagnostic pop
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#endif
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#endif // BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
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